Pure practical reason is the opposite to impure (or sensibly-determined) practical reason and appears in Immanuel Kant's Groundwork of the Metaphysics of Morals.
It is the reason that drives actions without any sensible incentives. Human reasoning chooses such actions simply because those actions are good in themselves; this is the nature of good will, which Kant argues is the only concept that is good without any justification, it is good in itself and is a derivative of a transcendental law which affects the way humans practically reason (see practical philosophy).
Famous quotes containing the words pure, practical and/or reason:
“Unto the pure all things are pure: but unto them that are defiled and unbelieving is nothing pure; but even their mind and conscience is defiled.”
—Bible: New Testament St. Paul, in Titus, 1:15.
See Lawrence on Puritans.
“War-making is one of the few activities that people are not supposed to view “realistically”; that is, with an eye to expense and practical outcome. In all-out war, expenditure is all-out, unprudent—war being defined as an emergency in which no sacrifice is excessive.”
—Susan Sontag (b. 1933)
“The reason why lovers are never bored together is that they are always talking of themselves.”
—François, Duc De La Rochefoucauld (1613–1680)